Nucleophilic Substitution at Heteroatoms-Identity Substitution Reactions at Phosphorus and Sulfur Centers: Do They Proceed in a Concerted (S_N2) or Stepwise (A-E) Way?

ABSTRACT: The mechanisms of three selected identity substitution reactions at phosphorus and sulfur occurring with stereospecific inversion have been investigated using density functional theory (DFT). The first identity reaction between methoxyl anion and methyl ethylphenylphosphinate 1 reported in 1963 has been shown to proceed in a stepwise fashion according to the addition-elimination (A-E) mechanism involving formation of a pentacoordinate phosphorus intermediate (TBI-1). In contrast, the results of DFT studies of the identity chloride exchange reaction in (ethoxy)ethylphosphonochloridothionate 3 in acetone solution provided evidence that it proceeds synchronously according to the classical Ingold's S_N2-P mechanism. DFT calculations of the methoxyl-methoxy exchan

SUBMITTER: Mikolajczyk M 

PROVIDER: S-EPMC8839028 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature